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i would not worry with the bracket hanging down. mine sticks down like that on my rivercat. It went 95.5mph (best) with the bracket not hanging down and I changed over to another bracket that does it its posted a best of 97.5mph, So I feel certain its not an issue. In other words, its not worth the trouble of messing with unless you just dont like it.
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32" carbon rivercat single 4s 102mph, 27” mini Rivercat 92mph, kbb34 91mph, jessej micro cat(too fast) was -
Oh, a suggestion for your bracket hanging too low... You can just add a little ramp from hull to bracket if you think it'll create drag. Indeed it will create air resistance, question is if it's enough to bother with it. In your case it barely steps out, so I would probably just shave off some more on that corner to smooth it out better. It's not a bad idea to make everything as aerodynamic as possible.Comment
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Thank you. It would have been substantially easier, and cheaper, to listen to you and jmscard. Unfortunately I continue to take the road less traveled and find myself dealing with lots of new questions. :) I really like the looks of the KBB rudder and it's going to be an easy swap out if/when I hit something in the water, so hopefully the extra effort will pay off down the road. I paid someone to print me up a custom 3D bracket. Hopefully it works out.
The back dimension (that sits flush with the hull) is 54mm wide by 28mm tall. The piece extends out 42mm and the small piece that meets up with the rudder is 25mm tall by 24mm wide. It's also contoured down from the top so the rudder sits low enough to hopefully meet up with the hydraulic arms. There are holes on the top that are 10.5mm wide and 10mm deep...these will allow me to install a 3mm x 10mm bolt into the hole and connect the rudder. After everything is mounted, I"ll have to either print another top and bottom plate or I will try to find some way to cover up the holes. The holes in the back are U shaped and will hopefully be wide enough to hold some locknuts.
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The mount is going to be printed using carbon fiber PLA material. http://www.proto-pasta.com/shop/cfpla I made it as thick as possible so it should be strong enough to support the load. I'll post some pictures when I get the actual 3D printed design in the next day or so.Last edited by fidelity101; 02-13-2015, 02:51 PM.Comment
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After two different 3D molds, a lot of grinding and filling, adding some brass 6/32 inserts and some JB weld to hold it all together...here is the finished product. It looks pretty impressive to me! :) The top and bottom of the rudder extension is a thick piece of lexan plastic that was sanded to remove the sheen and then painted black so I can access the internal bolts that hold the rudder in place. It came out pretty well I think. Now I need to install the Leopard motors and ESC's.
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I still haven't tightened down the stingers yet as I'm curious if anyone knows a good starting point for the angle of attack. Should I start at 0 degrees?Comment
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Where there is a will....
Great work!!!!Too many boats, not enough time...
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Thank you. :)
Now I'm looking closer at these water inlets and one is already loose. I used an exacto knife and cut marks at various angles before laying in a little jb weld. It seems to be holding so I may just do it to the others as well. If that fails, I'll be carving for a long time trying to get rid of all this carbon fiber filled epoxy.
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From my experience, if they are lose, they weren't sanded enough. I had the same issue on my old boat as I was too lazy and lacked knowledge to prep it. Sand them in all directions with some rough grit (80) to increase grab, degrease both hull and tubing with denatured alcohol. Drill a hole same size as the tube, smear some epoxy onto the tube and slide it through. Wipe off the excess. Use some resin thickening additives to increase strength and make it thick enough to create a nice base for your pickups on the inside instead of having it run off. This way you can get the shape more square and neat. Wait for the epoxy to get a bit thicker before doing that.
I also recommend adding that slanted cut on the tubes so you don't have to grind them down later to match the sponson angle as that doesn't come out as clean. And since yours got loose, the water will get through and at this point you're almost better off redoing them. Adding more epoxy or JB weld will just hold it till you have to mess with them again. If the piping is smooth, nothing will hold it.
Don't need to angle the tubes either like the original ones as the bottom cut out shape (teardrop) is what matters in getting more water in. Mine are vertical and it's crazy how much waterflow is coming out of the outlets even at slow speeds. And you don't really need those nozzles soldered on. That's just personal preference and isn't needed imo. Any 3-4mm tubing will sit tight enough. I've never had mine detach unless you use too small a brass pipe and large hoses.Comment
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^^^
What he said!
Also, IMO, no matter how well these tubes are epoxied, because it is round and only so much sanding/roughing up one can do, I added a support at the end of the tube. This is a tricky issue: anytime you connect/disconnect the hoses, a
lot of twisting and pulling, shoving is placed upon the joint.
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That's a great idea tlandauer...removing the blue water tube is what caused the pipe to dislodge in the first place. If it happens again, I'm going to bend them down and make a wooden support structure to hold them in place. Seems to be an easier alternative than trying to grind out a puddle of carbon fiber filled epoxy. Until then, the JB weld really did the trick as the pipe is locked in place so I'm going to leave it alone until it separates again.
Tear drop shapes have been added to the bottom of the hull where the intakes are. I used the Dremel part recemmended by TheShaddix (Thank you)
Now for the next challenge: One of the stingers is installed at an off angle. I'll have to take pictures tonight, but it appears that one of the stingers is 2-3mm off center meaning the prop is angled out towards the side 2-3mm rather than being straight back and parallel to the sponsons. The portion that attaches to the vertical section of the hull seems to be in the proper place, but the square plate with 4 holes that mounts to the underside of the hull is about 1/8-1/16" to far to the outside of the hull. Do you think the negative effects will be minimal or should I go ahead and fix it now? The correct way to fix it will be to remove the part, add another layer or two of carbon fiber to the inside of the boat, epoxy it down, fill the holes, drill new holes and reinstall. It's going to take a few days to fix it. If the small angle isn't that big of a deal, I might just leave it alone until I can buy some of the JBB stingers and do it the right way. Since I've never installed stingers before, I'm curious how much work that would entail as well as it looks like the copper tube is epoxied inside the hull.Last edited by fidelity101; 02-19-2015, 04:47 PM.Comment
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You might want to fix that if it's as drastic as 2-3 degrees. You can find out how much it needs to move to the side in order to get it straight once you unbolt the mount, then all you need to do is shift the holes by that much. I know the feeling, though, as my hpr has a similar issue. The original builder mounted one of the stingers about 3-4mm further than the other, visually it's quite noticeable as one of the props is offset length wise. I completely understand someone making such a mistake as it takes practice to drill precisely, but what I don't get is how one would leave it as it is and be ok with that!Comment
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The stinger that's visually out of alignment is about 3mm (thickness of the bolt) further to the outside of the hull. I'm going to have to figure out an accurate way to measure the current placement so I can figure out exactly how many degrees it's off but it's noticeable. Unfortunately, it's not far enough out that I can just drill new holes so I'd have to expand the current holes to move it, which might be too wide for the bottom plate to cover up. Hopefully that's not the case but time will tell.
Note: This measurement was incorrect as I was basing the "misalignment" off the distance from the inside hull section to the stinger rather than using a ruler to measure the distance from sponson to the stinger. Looking at the hull, you can see the measurements are different...but that's not the measurement that matters. My mistake.
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Right stinger
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If that's the case, you can always make some CF or aluminum plates to create new bases for your mounts. I guess they have to be thin so you still have the vertical adjustment. Or you can just mount them to the new location, then create a neat fillet with black epoxy to cover the old holes.
The best way to get the angle right is to line up a straight ruler to the sponson and check the stinger is parallel to it.Comment
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I should have asked for the best way to measure the alignment before putting foot in mouth. The right stinger is 1mm off from the portion of the stinger closest to the hull to the furthest distance out. The other one is 0.5mm off. They look different but I believe that's because one is 1mm in while the other one is 0.5mm out. I think I can probably loosen the screws and move the stingers in and out a bit to make up the difference since it's so incredibly small. Thanks for the ruler tip!
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The next question is, how tight do you make the stingers? There is a circular screw which seems to hold two black plastic pieces on each side of the round portion of the stinger inside the hull. That circle goes in about 2/3rds of the way before it becomes to hard to turn with my fingers. I used a wrench to turn it until it was snug, so now it's sticking out about 1.5mm.
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Since the stinger is 92mm long, the 1mm difference is about 0.6 degrees off. The one that's 0.5mm off translates to about 0.3 degrees off. I think that's acceptable. :)Last edited by fidelity101; 02-19-2015, 04:56 PM.Comment
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for the little nut that holds the stinger in its cup drop a bit of locktite as that nut will come lose eventually. As for the angle discrepancy, that's not a big deal. However, if it isn't difficult to get right, then why won't you? If anything, you can drill the holes one step larger and slide the stinger support bases to the right position and get it 100%, you'll be glad you did it knowing it's perfect. I know it would drive me crazy knowing something is offset when I could have done it better. And if your boat ever has any weird turning issues and you try to troubleshoot, you'll know this is definitely not the culprit anymore!Comment
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